Related
I have a text column that contains values like CN-CHGO-BNSF.
I need to reverse the order of the segments between hyphens. So the example above would be converted to BNSF-CHGO-CN. I can easily do this in C# code, but here I could optimize my task if I could do it within a query.
Is there any way to do this in a SQL query? I'm using Entity Framework and SQL Server. Is this possible?
The number of segments will be one or more. (The number of hyphens will be zero or more.)
Examples
Input
Output
BNSF
BNSF
CHGO-BNSF
BNSF-CHGO
CN-CHGO-BNSF
BNSF-CHGO-CN
FXE-EAGPA-BNSF-ROBSP-(RVPR)
(RVPR)-ROBSP-BNSF-EAGPA-FXE
With SQL Server 2022, it looks like STRING_SPLIT is being added (which I'm not currently using). I don't know if that could be used for this.
If you have a maximum number of positions, you can use a bit of JSON in concert with concat()
Example
Declare #YourTable Table ([SomeCol] varchar(50)) Insert Into #YourTable Values
('BNSF')
,('CHGO-BNSF')
,('CN-CHGO-BNSF')
,('FXE-EAGPA-BNSF-ROBSP-(RVPR)')
Select A.*
,NewVal = stuff( concat('-'+JSON_VALUE(JS,'$[6]')
,'-'+JSON_VALUE(JS,'$[5]')
,'-'+JSON_VALUE(JS,'$[4]')
,'-'+JSON_VALUE(JS,'$[3]')
,'-'+JSON_VALUE(JS,'$[2]')
,'-'+JSON_VALUE(JS,'$[1]')
,'-'+JSON_VALUE(JS,'$[0]')
),1,1,'')
From #YourTable A
Cross Apply (values ( '["'+replace(string_escape(SomeCol,'json'),'-','","')+'"]' ) ) B(JS)
Results
EDIT Using String_AGG
Select A.*
,B.NewValue
From #YourTable A
Cross Apply ( Select NewValue = string_agg(value,'-') within group (ORDER BY convert(int,[key]) desc)
from openjson( '["'+replace(string_escape(SomeCol,'json'),'-','","')+'"]' )
) B
Please try the following solution.
It is generic and will work for any number of tokens in a column.
It is using XML and XQuery to tokenize tokens in a column.
After that XQuery's FLWOR expression is traversing tokens in a reverse order via order by $pos descending.
SQL
-- DDL and sample data population, start
DECLARE #tbl TABLE (ID INT IDENTITY PRIMARY KEY, tokens VARCHAR(MAX));
INSERT Into #tbl (tokens) VALUES
('BNSF'),
('CHGO-BNSF'),
('CN-CHGO-BNSF'),
('FXE-EAGPA-BNSF-ROBSP-(RVPR)');
-- DDL and sample data population, end
DECLARE #separator CHAR(1) = '-';
SELECT t.*
, REPLACE(c.query('
for $x in /root/r/text()
let $pos := count(/root/r[. << $x[1]])
order by $pos descending
return data($x)
').value('.','VARCHAR(MAX)'),SPACE(1), #separator) AS Result
FROM #tbl AS t
CROSS APPLY (SELECT TRY_CAST('<root><r><![CDATA[' +
REPLACE(tokens, #separator, ']]></r><r><![CDATA[') +
']]></r></root>' AS XML)) AS t1(c);
Output
ID
tokens
Result
1
BNSF
BNSF
2
CHGO-BNSF
BNSF-CHGO
3
CN-CHGO-BNSF
BNSF-CHGO-CN
4
FXE-EAGPA-BNSF-ROBSP-(RVPR)
(RVPR)-ROBSP-BNSF-EAGPA-FXE
I have column with different pattern of string for each records let's call it [Description]. Here's the sample of records
[Description]
-qwetw MANN/1234556/DATE/030621/B/C/ACC/DIFF+AA11000532
-qwerty 123456789/06/29/2021/ACC./DONE/CLOSED+06+AA11001234
-qwert 123456789101213/-/BACK/300621/Rekening/Tutup+06+ZZZ21001123A
I want only pick the last number order - so the output would be:
[Description]
-11000532
-11001234
-21001123
Is there any function how to get it?
Thanks
Please try the following solutions.
First solution is for SQL Server 2017 onwards.
It is working by implementing the following steps:
It is tokenizing column value as XML.
Last token is our goal, i.e. (/root/r[last()]/text())[1]
TRIM() removes unwanted chars.
Second solution is for SQL Server 2012. It is much more involving.
SQL 2017
-- DDL and sample data population, start
DECLARE #tbl TABLE (ID INT IDENTITY PRIMARY KEY, Tokens VARCHAR(4000));
INSERT INTO #tbl VALUES
('-qwetw MANN/1234556/DATE/030621/B/C/ACC/DIFF+AA11000532'),
('-qwert 123456789101213/-/BACK/300621/Rekening/Tutup+06+ZZZ21001123A'),
('-qwerty 123456789/06/29/2021/ACC./DONE/CLOSED+06+AA11001234');
-- DDL and sample data population, end
DECLARE #separator CHAR(1) = '+'
, #CharsToRemove VARCHAR(100) = 'AZ';
SELECT ID, tokens
, TRIM(#CharsToRemove FROM token) AS Result
FROM #tbl
CROSS APPLY (VALUES (TRY_CAST('<root><r><![CDATA[' +
REPLACE(tokens, #separator, ']]></r><r><![CDATA[') +
']]></r></root>' AS XML))) AS t(c)
CROSS APPLY (VALUES (c.value('(/root/r[last()]/text())[1]', 'VARCHAR(256)'))) AS t2(token);
SQL 2012
SELECT ID, tokens
, (
SELECT SUBSTRING(token, number, 1)
FROM #tbl AS c
CROSS APPLY (
SELECT DISTINCT number
FROM master..spt_values
WHERE number BETWEEN 1 AND LEN(token)
) V
WHERE c.ID = p.ID
FOR XML PATH('r'), TYPE, ROOT('root')
)
.query('for $x in /root/r
return if (xs:int($x) instance of xs:int) then $x
else ()')
.query('/r/text()').value('.', 'BIGINT') AS Result
FROM #tbl AS p
CROSS APPLY (VALUES (TRY_CAST('<root><r><![CDATA[' +
REPLACE(tokens, #separator, ']]></r><r><![CDATA[') +
']]></r></root>' AS XML))) AS t(c)
CROSS APPLY (VALUES (c.value('(/root/r[last()]/text())[1]', 'VARCHAR(256)'))) AS t2(token);
Output
+----+---------------------------------------------------------------------+----------+
| ID | tokens | Result |
+----+---------------------------------------------------------------------+----------+
| 1 | -qwetw MANN/1234556/DATE/030621/B/C/ACC/DIFF+AA11000532 | 11000532 |
| 2 | -qwert 123456789101213/-/BACK/300621/Rekening/Tutup+06+ZZZ21001123A | 21001123 |
| 3 | -qwerty 123456789/06/29/2021/ACC./DONE/CLOSED+06+AA11001234 | 11001234 |
+----+---------------------------------------------------------------------+----------+
Your example is tricky, as it is having alphabets also as part of the order number.
I am assuming your datatype is VARCHAR(4000) and accordingly, I have applied substring in the end with 4000, to make it simpler in the end.
DECLARE #table table(Description varchar(4000))
insert into #table values
('-qwetw MANN/1234556/DATE/030621/B/C/ACC/DIFF+AA11000532')
,('-qwert 123456789101213/-/BACK/300621/Rekening/Tutup+06+ZZZ21001123A')
,('-qwerty 123456789/06/29/2021/ACC./DONE/CLOSED+06+AA11001234');
SELECT SUBSTRING(REVERSE(SUBSTRING(REVERSE(Description),1,CHARINDEX('+',REVERSE(Description)))),PATINDEX('%[1-9]%',REVERSE(SUBSTRING(REVERSE(Description),1,CHARINDEX('+',REVERSE(Description))))),4000) as ordernumber FROM #table
ordernumber
11000532
21001123A
11001234
I wish to loop through two comma-separated values and perform an insert
As an example lets consider two variables
Declare #Qid= 1,4,6,7,8 #Answers = 4,4,3,2,3
set #pos = 0
set #len = 0
WHILE CHARINDEX(',', #Answers, #pos+1)>0
BEGIN
set #len = CHARINDEX(',', #Answers, #pos+1) - #pos
set #value = SUBSTRING(#Answers, #pos, #len)
insert into table values(#fdid,#Qid,#fusid, #value) -- i need Qid also
set #pos = CHARINDEX(',', #Answers, #pos+#len) +1
END
Using this loop I am able to extract #Answers and can perform insert. But I wish to extract #Qid and insert inside the loop.
edit
for more clarity it is a feedback module. my result table have Qid and Answer field. Answers are ratings (1 to 5). The values we get in variables #Qid and #Answers are sequential. which means 1st answer will be for 1st question and so on.
edit
as per Shnugo's Answer
Declare #Qid varchar(100)= '1,4,6,7,8', #Answers varchar(100)= '4,4,3,2,3'
DECLARE #tbl TABLE(ID INT IDENTITY, Questions VARCHAR(100),Answers VARCHAR(100));
INSERT INTO #tbl VALUES(#Qid,#Answers)
INSERT INTO table(FeedbackId,QuestionId,FeedbackUserId,Answer)
SELECT 1,
A.qXml.value('(/x[sql:column("B.QuestionCount")])[1]','int') AS QuestionNumber,3
,A.aXml.value('(/x[sql:column("B.QuestionCount")])[1]','int') AS AnwerNumber
FROM #tbl t
CROSS APPLY(SELECT CAST('<x>' + REPLACE(#Qid,',','</x><x>') + '</x>' AS XML)
,CAST('<x>' + REPLACE(#Answers,',','</x><x>') + '</x>' AS XML)) A(qXml,aXml)
CROSS APPLY(SELECT TOP(A.qXml.value('count(/x)','int')) ROW_NUMBER() OVER(ORDER BY (SELECT NULL)) FROM master..spt_values) B(QuestionCount)
I'd prefer Zhorov's JSON answer (needs v2016+).
If you use a SQL-Server below 2016 you might use this position-safe XML-based solution:
A mockup table to simulate your issue with two different rows.
DECLARE #tbl TABLE(ID INT IDENTITY, Questions VARCHAR(100),Answers VARCHAR(100));
INSERT INTO #tbl VALUES('1,4,6,7,8','4,4,3,2,3')
,('1,2,3','4,5,6');
--The query
SELECT t.*
,A.qXml.value('(/x[sql:column("B.QuestionCount")])[1]','int') AS QuestionNumber
,A.aXml.value('(/x[sql:column("B.QuestionCount")])[1]','int') AS AnwerNumber
FROM #tbl t
CROSS APPLY(SELECT CAST('<x>' + REPLACE(t.Questions,',','</x><x>') + '</x>' AS XML)
,CAST('<x>' + REPLACE(t.Answers,',','</x><x>') + '</x>' AS XML)) A(qXml,aXml)
CROSS APPLY(SELECT TOP(A.qXml.value('count(/x)','int')) ROW_NUMBER() OVER(ORDER BY (SELECT NULL)) FROM master..spt_values) B(QuestionCount);
The idea in short:
We need a CROSS APPLY and some string methods to transform something like 1,2,3 to an xml like <x>1</x><x>2</x><x>3</x>.
Now we can use value() with XQuery count() to find the actual count of questions.
We need one more CROSS APPLY with a computed TOP() clause to get a set of running number from 1 to n with n=countOfQuestions. I do this against master..spt_values. This is just a well-filled standard table... We do not need the values, just any set to create the counter...
Finally we can use .value() in connection with sql:column() in order to fetch the question and the corresponding answer by their positions.
UPDATE: Non-tabular data
If you do not get these CSV parameters as a table you can use this:
Declare #Qid varchar(100)= '1,4,6,7,8', #Answers varchar(100)= '4,4,3,2,3'
--INSERT INTO table(FeedbackId,QuestionId,FeedbackUserId,Answer)
SELECT 1
,A.qXml.value('(/x[sql:column("B.QuestionCount")])[1]','int') AS QuestionNumber
,3
,A.aXml.value('(/x[sql:column("B.QuestionCount")])[1]','int') AS AnwerNumber
FROM (SELECT CAST('<x>' + REPLACE(#Qid,',','</x><x>') + '</x>' AS XML)
,CAST('<x>' + REPLACE(#Answers,',','</x><x>') + '</x>' AS XML)) A(qXml,aXml)
CROSS APPLY(SELECT TOP(A.qXml.value('count(/x)','int')) ROW_NUMBER() OVER(ORDER BY (SELECT NULL)) FROM master..spt_values) B(QuestionCount);
If you use SQL Server 2016 or higher, you may try to use the next JSON-based approach to map questions and answers by their positions in the input strings. You need to transform the input strings into valid JSON arrays and then use OPENJSON() with default schema to parse the arrays. The result is a table, with columns key, value and type and the key column holds the index of the element in the specified array.
Note, that STRING_SPLIT() function does not guarantee the order of the rows and the output rows might be in any order.
Statement:
DECLARE #Qid nvarchar(max) = N'1,4,6,7,8'
DECLARE #Answers nvarchar(max) = N'4,4,3,2,3'
-- Build your INSERT statement as you expect
-- INSERT INTO Table ...
SELECT j1.[value] AS Qid, j2.[value] AS Answers
FROM OPENJSON(CONCAT(N'[', #Qid, N']')) j1
JOIN OPENJSON(CONCAT(N'[', #Answers, N']')) j2 ON j1.[key] = j2.[key]
Result from the SELECT statement:
Qid Answers
1 4
4 4
6 3
7 2
8 3
You have not described relationship of question and its answers. I feel its one to one relationship and for that, I have given the answer.
declare #Qid varchar(200)= '1,4,6,7,8' , #Answers varchar(200) = '4,4,3,2,3'
;with cte
as(
select id, data qid from dbo.Split (#qid, ',')
),
cte1 as
(
select id, data ansid from dbo.Split (#answers, ',')
)
--insert into tablename
select
qid, ansid from cte join cte1 on cte.id = cte1.id
Result will be:
qid ansid
1 4
4 4
6 3
7 2
8 3
See other option for later version of sqlserver : Split function equivalent in T-SQL?
I have a field which is a concatenation of single letters. I am trying to order these strings within a view. These values can't be hard coded as there are too many. Is someone able to provide some guidance on the function to use to achieve the desired output below? I am using MSSQL.
Current output
CustID | Code
123 | BCA
Desired output
CustID | Code
123 | ABC
I have tried using a UDF
CREATE FUNCTION [dbo].[Alphaorder] (#str VARCHAR(50))
returns VARCHAR(50)
BEGIN
DECLARE #len INT,
#cnt INT =1,
#str1 VARCHAR(50)='',
#output VARCHAR(50)=''
SELECT #len = Len(#str)
WHILE #cnt <= #len
BEGIN
SELECT #str1 += Substring(#str, #cnt, 1) + ','
SET #cnt+=1
END
SELECT #str1 = LEFT(#str1, Len(#str1) - 1)
SELECT #output += Sp_data
FROM (SELECT Split.a.value('.', 'VARCHAR(100)') Sp_data
FROM (SELECT Cast ('<M>' + Replace(#str1, ',', '</M><M>') + '</M>' AS XML) AS Data) AS A
CROSS APPLY Data.nodes ('/M') AS Split(a)) A
ORDER BY Sp_data
RETURN #output
END
This works when calling one field
ie.
Select CustID, dbo.alphaorder(Code)
from dbo.source
where custid = 123
however when i try to apply this to top(10) i receive the error
"Invalid length parameter passed to the LEFT or SUBSTRING function."
Keeping in mind my source has ~4million records, is this still the best solution?
Unfortunately i am not able to normalize the data into a separate table with records for each Code.
This doesn't rely on a id column to join with itself, performance is almost as fast
as the answer by #Shnugo:
SELECT
CustID,
(
SELECT
chr
FROM
(SELECT TOP(LEN(Code))
SUBSTRING(Code,ROW_NUMBER() OVER(ORDER BY (SELECT NULL)),1)
FROM sys.messages) A(Chr)
ORDER by chr
FOR XML PATH(''), type).value('.', 'varchar(max)'
) As CODE
FROM
source t
First of all: Avoid loops...
You can try this:
DECLARE #tbl TABLE(ID INT IDENTITY, YourString VARCHAR(100));
INSERT INTO #tbl VALUES ('ABC')
,('JSKEzXO')
,('QKEvYUJMKRC');
--the cte will create a list of all your strings separated in single characters.
--You can check the output with a simple SELECT * FROM SeparatedCharacters instead of the actual SELECT
WITH SeparatedCharacters AS
(
SELECT *
FROM #tbl
CROSS APPLY
(SELECT TOP(LEN(YourString)) ROW_NUMBER() OVER(ORDER BY (SELECT NULL)) FROM master..spt_values) A(Nmbr)
CROSS APPLY
(SELECT SUBSTRING(YourString,Nmbr,1))B(Chr)
)
SELECT ID,YourString
,(
SELECT Chr As [*]
FROM SeparatedCharacters sc1
WHERE sc1.ID=t.ID
ORDER BY sc1.Chr
FOR XML PATH(''),TYPE
).value('.','nvarchar(max)') AS Sorted
FROM #tbl t;
The result
ID YourString Sorted
1 ABC ABC
2 JSKEzXO EJKOSXz
3 QKEvYUJMKRC CEJKKMQRUvY
The idea in short
The trick is the first CROSS APPLY. This will create a tally on-the-fly. You will get a resultset with numbers from 1 to n where n is the length of the current string.
The second apply uses this number to get each character one-by-one using SUBSTRING().
The outer SELECT calls from the orginal table, which means one-row-per-ID and use a correalted sub-query to fetch all related characters. They will be sorted and re-concatenated using FOR XML. You might add DISTINCT in order to avoid repeating characters.
That's it :-)
Hint: SQL-Server 2017+
With version v2017 there's the new function STRING_AGG(). This would make the re-concatenation very easy:
WITH SeparatedCharacters AS
(
SELECT *
FROM #tbl
CROSS APPLY
(SELECT TOP(LEN(YourString)) ROW_NUMBER() OVER(ORDER BY (SELECT NULL)) FROM master..spt_values) A(Nmbr)
CROSS APPLY
(SELECT SUBSTRING(YourString,Nmbr,1))B(Chr)
)
SELECT ID,YourString
,STRING_AGG(sc.Chr,'') WITHIN GROUP(ORDER BY sc.Chr) AS Sorted
FROM SeparatedCharacters sc
GROUP BY ID,YourString;
Considering your table having good amount of rows (~4 Million), I would suggest you to create a persisted calculated field in the table, to store these values. As calculating these values at run time in a view, will lead to performance problems.
If you are not able to normalize, add this as a denormalized column to the existing table.
I think the error you are getting could be due to empty codes.
If LEN(#str) = 0
BEGIN
SET #output = ''
END
ELSE
BEGIN
... EXISTING CODE BLOCK ...
END
I can suggest to split string into its characters using referred SQL function.
Then you can concatenate string back, this time ordered alphabetically.
Are you using SQL Server 2017? Because with SQL Server 2017, you can use SQL String_Agg string aggregation function to concatenate characters splitted in an ordered way as follows
select
t.CustId, string_agg(strval, '') within GROUP (order by strval)
from CharacterTable t
cross apply dbo.SPLIT(t.code) s
where strval is not null
group by CustId
order by CustId
If you are not working on SQL2017, then you can follow below structure using SQL XML PATH for concatenation in SQL
select
CustId,
STUFF(
(
SELECT
'' + strval
from CharacterTable ct
cross apply dbo.SPLIT(t.code) s
where strval is not null
and t.CustId = ct.CustId
order by strval
FOR XML PATH('')
), 1, 0, ''
) As concatenated_string
from CharacterTable t
order by CustId
I'm using SQL Server and I'm trying to find results but I would like to get the results in the same order as I had input the conditions.
My code:
SELECT
AccountNumber, EndDate
FROM
Accounts
WHERE
AccountNumber IN (212345, 312345, 145687, 658975, 256987, 365874, 568974, 124578, 125689) -- I would like the results to be in the same order as these numbers.
Here is an in-line approach
Example
Declare #List varchar(max)='212345, 312345, 145687, 658975, 256987, 365874, 568974, 124578, 125689'
Select A.AccountNumber
,A.EndDate
From Accounts A
Join (
Select RetSeq = Row_Number() over (Order By (Select null))
,RetVal = v.value('(./text())[1]', 'int')
From (values (convert(xml,'<x>' + replace(#List,',','</x><x>')+'</x>'))) x(n)
Cross Apply n.nodes('x') node(v)
) B on A.AccountNumber = B.RetVal
Order By B.RetSeq
EDIT - the subquery Returns
RetSeq RetVal
1 212345
2 312345
3 145687
4 658975
5 256987
6 365874
7 568974
8 124578
9 125689
You can replace IN with a JOIN, and set a field for ordering, like this:
SELECT AccountNumber , EndDate
FROM Accounts a
JOIN (
SELECT 212345 AS Number, 1 AS SeqOrder
UNION ALL
SELECT 312345 AS Number, 2 AS SeqOrder
UNION ALL
SELECT 145687 AS Number, 3 AS SeqOrder
UNION ALL
... -- and so on
) AS inlist ON inlist.Number = a.AccountNumber
ORDER BY inlist.SeqOrder
I will offer one more approach I just found out, but this needs v2016. Regrettfully the developers forgot to include the index into the resultset of STRING_SPLIT(), but this would work and is documented:
A solution via FROM OPENJSON():
DECLARE #str VARCHAR(100) = 'val1,val2,val3';
SELECT *
FROM OPENJSON('["' + REPLACE(#str,',','","') + '"]');
The result
key value type
0 val1 1
1 val2 1
2 val3 1
The documentation tells clearly:
When OPENJSON parses a JSON array, the function returns the indexes of the elements in the JSON text as keys.
This is not an answer, just some test-code to check John Cappelletti's approach.
DECLARE #tbl TABLE(ID INT IDENTITY,SomeGuid UNIQUEIDENTIFIER);
--Create more than 6 mio rows with an running number and a changing Guid
WITH tally AS (SELECT ROW_NUMBER()OVER(ORDER BY (SELECT NULL)) AS Nmbr
FROM master..spt_values v1
CROSS JOIN master..spt_values v2)
INSERT INTO #tbl
SELECT NEWID() from tally;
SELECT COUNT(*) FROM #tbl; --6.325.225 on my machine
--Create an XML with nothing more than a list of GUIDs in the order of the table's ID
DECLARE #xml XML=
(SELECT SomeGuid FRom #tbl ORDER BY ID FOR XML PATH(''),ROOT('root'),TYPE);
--Create one invalid entry
UPDATE #tbl SET SomeGuid = NEWID() WHERE ID=10000;
--Read all GUIDs out of the XML and number them
DECLARE #tbl2 TABLE(Position INT,TheGuid UNIQUEIDENTIFIER);
INSERT INTO #tbl2(Position,TheGuid)
SELECT ROW_NUMBER() OVER(ORDER BY (SELECT NULL))
,g.value(N'text()[1]',N'uniqueidentifier')
FROM #xml.nodes(N'/root/SomeGuid') AS A(g);
--then JOIN them via "Position" and check,
--if there are rows, where not the same values get into the same row.
SELECT *
FROM #tbl t
INNER JOIN #tbl2 t2 ON t2.Position=t.ID
WHERE t.SomeGuid<>t2.TheGuid;
At least in this simple case I always get exactly only the one record back which was invalidated...
Okay, after some re-thinking I'll offer the ultimative XML based type-safe and sort-safe splitter:
Declare #List varchar(max)='212345, 312345, 145687, 658975, 256987, 365874, 568974, 124578, 125689';
DECLARE #delimiter VARCHAR(10)=', ';
WITH Casted AS
(
SELECT (LEN(#List)-LEN(REPLACE(#List,#delimiter,'')))/LEN(REPLACE(#delimiter,' ','.')) + 1 AS ElementCount
,CAST('<x>' + REPLACE((SELECT #List AS [*] FOR XML PATH('')),#delimiter,'</x><x>')+'</x>' AS XML) AS ListXml
)
,Tally(Nmbr) As
(
SELECT TOP((SELECT ElementCount FROM Casted)) ROW_NUMBER() OVER(ORDER BY (SELECT NULL)) FROM master..spt_values v1 CROSS JOIN master..spt_values v2
)
SELECT Tally.Nmbr AS Position
,(SELECT ListXml.value('(/x[sql:column("Tally.Nmbr")])[1]','int') FROM Casted) AS Item
FROM Tally;
The trick is to create a list of running numbers with the fitting number of element (a number's table was even better) and to pick the elements according to their position.
Hint: This is rather slow...
UPDATE: even better:
WITH Casted AS
(
SELECT (LEN(#List)-LEN(REPLACE(#List,#delimiter,'')))/LEN(REPLACE(#delimiter,' ','.')) + 1 AS ElementCount
,CAST('<x>' + REPLACE((SELECT #List AS [*] FOR XML PATH('')),#delimiter,'</x><x>')+'</x>' AS XML)
.query('
for $x in /x
return <x p="{count(/x[. << $x])}">{$x/text()[1]}</x>
') AS ListXml
)
SELECT x.value('#p','int') AS Position
,x.value('text()[1]','int') AS Item
FROM Casted
CROSS APPLY Casted.ListXml.nodes('/x') AS A(x);
Elements are create as
<x p="99">TheValue</x>
Regrettfully the XQuery function position() is not available to retrieve the value. But you can use the trick to count all elements before a given node. this is scaling badly, as this count must be performed over and over. The more elements the worse it goes...
UPDATE2: With a known count of elements one might use this (much better performance)
Use XQuery to iterate a literally given list:
WITH Casted AS
(
SELECT (LEN(#List)-LEN(REPLACE(#List,#delimiter,'')))/LEN(REPLACE(#delimiter,' ','.')) + 1 AS ElementCount
,CAST('<x>' + REPLACE((SELECT #List AS [*] FOR XML PATH('')),#delimiter,'</x><x>')+'</x>' AS XML)
.query('
for $i in (1,2,3,4,5,6,7,8,9)
return <x p="{$i}">{/x[$i]/text()[1]}</x>
') AS ListXml
)
SELECT x.value('#p','int') AS Position
,x.value('text()[1]','int') AS Item
FROM Casted
CROSS APPLY Casted.ListXml.nodes('/x') AS A(x);
In Azure SQL, there is now extended version of STRING_SPLIT which also can return the order of items if the third optional argument enable_ordinal is set to 1.
Then this simple task is finally easy:
DECLARE #string AS varchar(200) = 'a/b/c/d/e'
DECLARE #position AS int = 3
SELECT value FROM STRING_SPLIT(#string, '/', 1) WHERE ordinal = #position
Unfortunately not available in SQL Server 2019, only in Azure for now, lets hope it will be in SQL Server 2022.